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Thermo-chemical conversion of biomass is a promising technological alternative for producing renewable fuel and reducing waste disposal. This simulation study includes the first attempt to perform co-gasification of algae-plastic waste for H2-enriched gaseous fuel production. An Aspen Plus-based simulation model was developed to evaluate the influence of gasifier temperature and equivalence ratio on the syngas composition, heating value, and carbon conversion efficiency. Simulation results indicated that the rise in gasifier temperature favoured the H2 and CO formation, and further, plastic loading enhanced H2 production to a greater extent. It was observed that the product (H2 and CO) yield decreased significantly with the rise of the equivalence ratio. At the same time, CO2 formation increased due to more carbon conversion after enhancing O2 content in the gasifier. It was also noticed that the synergy of biomass and plastic waste significantly enhanced H2 content and improved heating value, leading to a produced energy-efficient gaseous product. It is inferred that H2-enriched feedstock acts as an H2 donor to the H2 deficient biomass. Based on the findings, consistency in the simulation results was observed compared with the previous literature. Hence, a mixture of biomass and plastic waste favours obtaining an energy-efficient renewable fuel that could be utilized for different applications.

A mathematical model for the catalytic autothermal reforming (ATR) reaction of synthetic crude glycerol to hydrogen in a fixed bed tubular reactor (FBTR) and over an in-house developed metal oxide catalyst is presented in this work. The heterogeneous model equations account for a two-phase system of solid catalyst and bulk feed gas. Also, the ATR of crude glycerol reaction scheme and intrinsic kinetic rate model over an active, selective, and stable nickel-based catalyst were integrated in the developed model. Also, the model was validated using experimental data generated in our labs for the ATR of synthetic crude glycerol. The modelling results adequately described the detailed gas product composition and distribution, temperature profiles, and conversion propagation in the axial direction of the fixed bed reactor over a wide range of reaction temperature (773−923 K) and weight-time (12.71−158.23 g cat·min·molC−1). The crude glycerol conversion predicted with the model showing a close resemblance to those obtained experimentally with an average absolute deviation (AAD) of less than 8%. The maximum crude glycerol conversion and hydrogen yield were found to be 92% and 3 mol hydrogen/mol crude glycerol, respectively. Also, the gas product concentration profile in the reactor was adequately described (90%) accuracy with a hydrogen concentration of 39 vol%.

Various feedstocks such as natural gas, glycerol, biomass, methanol, ethane, and other hydrocarbons can be reformed to generate hydrogen as a viable alternative source of renewable energy. Also, hydrogen is generated via other processes not associated with reforming including electrolysis, thermolysis, and photolysis. The reforming of the different feedstock for hydrogen reaction generally requires the utilization of heterogeneous catalysts to speed up the reactions and reduce the energy used up in the reaction. Experimental studies provide an understanding of the reaction mechanism and the nature of the reactants and products of the reaction. Computational studies involving density functional theory provide even greater insights into these reactions. Its combination with machine learning provides huge potentials for the study and discovery of technologies for hydrogen production but remains underutilized. The use of both computational techniques has widely been adjudged as the most economical and precise means of screening multiple catalysts in the heterogeneous reactions involved in hydrogen production processes. This paper reviews the application of density functional theory and machine learning in thermochemical reactions associated with the production of hydrogen. It also highlights the state-of-the-art computational methodologies employed in the design of hydrogen production technologies such as methane pyrolysis, steam methane reforming, dry reforming of methane, and other reforming processes for hydrogen production. The current progress and knowledge gaps in the research and development of hydrogen production technologies from a computational point of view are also discussed.

The reforming of methane is an important industrial process, and reactor modeling and simulation is frequently employed as a design and analysis tool in understanding this process. While much research work is devoted to catalyst formulations, reaction mechanisms, and reactor designs, this review aims to summarize the literature concerning the simulation of methane reforming. Applications in industrial practice are highlighted, and the three main approaches to representing the reactions are briefly discussed. An overview of simulation studies focusing on methane reforming is presented. The three central methods for fixed-bed reactor modeling are discussed. Various approaches and modern examples are discussed, presenting their modeling methods and key findings. The overall objective of this paper is to provide a dedicated review of simulation work done for methane reforming and provide a reference for understanding this field and identifying possible new paths.

It is undeniable that oil and gas explorations are going on at a frantic pace due to excessive fossil fuel usage across the world. This has compelled us to explore isolated or even uninhabited places to meet the surging demand for oil and gas. There is no doubt that scientists and researchers worldwide are exploring more renewable energy sources to produce value-added products. In the last few years, biogas' usage as a reactant gas in the catalytic reforming process has emanated as an energy carrier to produce energy-efficient products, i.e., syngas and methanol. This review aimed to analyze the research works focusing on the biogas DR reactions and methanol production from biogas. The findings of some experimental studies have been presented in the form of graphs for important selective parameters as case studies. The overall impression from the review suggests that the performance of the reforming catalysts deteriorates regarding different operating conditions. Still, the improvement in syngas production has been reported by neglecting the effect of H2S impurity. Furthermore, various parameters have been discussed paragraphically to evaluate the catalytic performance in biogas dry reforming reactions and a check on catalyst synthesis methods. After that, a few scattered studies have been discussed on methanol synthesis using biogas as a feedstock.

Hydrocarbon reforming routes are renowned for producing a multitude of energy-effective renewable fuels and/or chemicals. In this study, Aspen HYSYS simulation software was employed to assess the feasibility of a biogas-to-methanol conversion process via coupling CH4 recycling and CO2 sequestration with the dry reforming of biogas. The results revealed that CH4 conversion dramatically enhanced via the recycling of unreacted CH4, followed by CO2 mitigation to a more considerable extent. Simulation runs were performed while varying the reactor pressure and temperature in the ranges of 1.0 to 2.5 bar and 700 to 900 °C, respectively. It was observed that the CO2 conversion decreased continuously as the pressure increased, while there were negligible differences in terms of CH4 conversion using the recycling loop, especially at temperatures of ≥800 °C. At 900 °C and 1 bar, the stoichiometric product (H2/CO) ratio, with CH4 conversion of 83.7% and CO2 conversion of 99.9%, was achieved. An increase in temperature did not significantly affect the WGSR, and 96.6% reactor conversion, with a H2/CO ratio of 1.98, was obtained at a temperature of 150 °C and a pressure of 1.0 bar. The reported study inferred that methanol can be produced at a rate of 24.7 kg h−1 using a biogas molar flow of 1.0 kg mol h−1 under the optimal conditions of 200 °C (temperature) and 100 bar (pressure), with a net thermal efficiency of 67.3%. Overall, it is concluded that biogas dry reforming could allow a sustainable methanol synthesis process with CO2 mitigation at a potentially lower cost, especially in rural areas.

A detailed computational fluid dynamics (CFD) model has been developed in this study for the water gas shift of untreated biogas reformate in both fixed bed and membrane reactors to gain insights into the interaction of 3Ni5Cu/Ce0.5Zr0.33Ca0.17 catalyst with fluid transport phenomena taking place in the reactor. The developed CFD model closely agreed with data from both literature and experiments. An average absolute deviation of 8.59% and 6.32% was obtained when the CFD model was validated with a fixed bed reactor and membrane reactor experiments respectively. The membrane reactor enabled equilibrium conversion at 2.95 gcat.h/mol CO weight-time with equilibrium conversion attained at lower weight-time and steam to carbon ratio of 3.4. Also, it was found that the counter-flow configuration resulted in better enhanced CO conversion, and the wall heat transfer coefficient above 8.6 W/m2/K had negligible on conversion, amounting to only a 1% increase in conversion for both reactors.

Tea residue, a common waste obtained from households and beverage industries, was studied as an efficient bio-sorbent for the extraction of methylene blue (MB) from textile industry effluents by varying key operational parameters such as pH, contact time and adsorbent dosage. Scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy (FT-IR) were used for the characterization of tea residue. This investigation found that the tea residue’s morphological structure and availability of selective functional groups are the main factors behind its high adsorption capacity. Adsorbent dosage and pH were found to be two important parameters that affect the efficiency of the adsorption process. Also, the contact time affected the removal efficiency of adsorbent—eventually reaching equilibrium after 105 min. The adsorbent has shown a maximum adsorption capacity of 181.2 mgg−1 at pH 10. The results showed that the equilibrium data fit the Langmuir isotherm very well and are best described by a pseudo-second-order kinetic model with a correlation coefficient of 0.99. For the mechanistic understanding of the adsorption transport process, the intraparticle diffusion model was used. In addition, the testing of experimental data for kinetic models was carried out by statistical analysis. The results of the FT-IR analysis showed that electrostatic interaction exists between MB and functional groups of tea residue. This study showed that the activated tea residue is not only a viable and economic alternative to other potential bio-sorbents and activated carbon but also has increased adsorption capacity and favorable kinetics.

CO2 capture performance of two imidazolium-based ionic liquids 1-Butyl-3-methylimidazolium Acetate [BMIM][Ac] and 1-propyl-3-methylimidazolium bis(trifluoro -methylsulfonyl)imide [PMIM][Tf2N] supported on a commercial Cu-BTC metal organic framework (HKUST-1) was investigated. The thermogravimetric analysis (TGA) was employed to analyse the impacts of ILs impregnation on the thermal stability of the composites. Furthermore, other characterization techniques such as powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) were used to confirm the successful incorporation of the ILs within the cages of HKUST-1. The as-synthesized ILs@HKUST-1 composites exhibited a stable crystal structure after the encapsulation of the ILs indicating that the structural features of the HKUST-1 support were retained and not impacted by the presence of ILs inside the pores. Moreover, the BET surface area and total pore volume of the ILs@HKUST-1 composites decreased considerably with the increase in IL loading in the composite which suggests the efficient incorporation of the ILs into the porous surface of the HKUST-1 support. Remarkably, the composite sorbent prepared with 5 wt% [bmim][Ac] exhibited the highest CO2 capacity in the low pressure region with almost double that of the pristine HKUST-1 at 303 K and 0.15 bar. On the other hand, the introduction of [pmim][Tf2N] into the pores of HKUST-1 did not show any enhancement in the CO2 uptake at all IL loadings. The samples also displayed a fast adsorption kinetics and a stable adsorption-regeneration performance up to ten cycles. The developed IL@HKUST-1 composites provide a great opportunity to design sorbent materials with excellent merits for potential industrial gas separation applications.

The kinetics of catalyst-aided desorption of CO2 from CO2-loaded MEA (5 mol/dm3) and blended MEA-MDEA (7 mol/dm3) solutions at CO2 loadings from 0.3 to 0.5 mol CO2/mol amine were studied over a Lewis acid catalyst (γ-Al2O3) and a Bronsted acid catalyst (H-ZSM-5) in an absorber–desorber CO2 capture bench-scale plant (columns of 0.051 m ID and height of 1.067 m) at temperatures of 348–368 K. The results showed that the conversion increases relative to no catalyst for MEA were 55 and 74% while for MEA-MDEA, they were 65 and 85.2% with γ-Al2O3 and H-ZSM-5, respectively. A comprehensive mechanistic LHHW rate model was developed for the catalytic CO2 desorption process.

The potential advantage of using supported ionic liquids (SILs) for CO2 capture applications has been investigated in this work. The impregnation of 1-ethyl-3-methylimidazolium Acetate [emim][Ac] into two voluminous metal–organic frameworks (MOF-177 and MIL-101) is evaluated using different synthesis methods. The performance of the composite sorbents for CO2 capture has been evaluated using various characterization techniques. The successful incorporation of [emim][Ac] into the pores of MOF-177 and MIL-101 have been confirmed using thermogravimetric analysis and Fourier transform infrared spectroscopy results. Furthermore, the porosity of the as-synthesized samples using different synthesis methods have been measured using N2 adsorption experiments to evaluate the changes in the specific surface areas and pore volumes upon the introduction of [emim][Ac] to the support materials. A significant decrease in the porosity was realized for the [emim][Ac]-confined samples especially when using wet impregnation synthesis method compared to the dry mixing approach. The crystal structures of the MOF-177 and MIL-101 were found to be maintained after the synthetic steps, with some reductions in the X-ray diffraction peak intensities. No improvements in the CO2 uptakes could be achieved for the MIL-101 samples using both synthesis strategies, whereas the [emim][Ac]@MOF-177 samples prepared using wet impregnation method, has shown a remarkable enhancement in the CO2 capacity up to 0.3 mmol/g at 0.15 bar and 303 K. Moreover, the adsorption kinetics in MOF-177 based samples was found to be significantly fast as depicted from the first order rate constant values. The [emim][Ac]@MOF-177 samples exhibited a substantially stable cyclic adsorption–desorption performance up to 10 successive cycles with a considerably fast desorption kinetics.

The current sources of our energy supply are plagued with many problems and the impact on the climate is of grave concern. Hydrogen (H2), when extracted from one of its many sources with carbon dioxide (CO2) capture, is considered a non-polluting, efficient and environmentally sustainable energy source. In this study, the control of a pilot-scale reformer for the production of H2 was studied. H2 was produced through the CO2 reforming of methane (CH4). An ANFIS approach was used to model the process. Type-2 fuzzy sets and systems was implemented as the fuzzy inference engine, which renders a piece-wise linearization of the nonlinear model. The generalized bell-shape membership functions were used and optimized based on empirical training data. This model was further used within an MPC framework to devise optimal control strategies. An unconstrained optimization method on the piece-wise quasi-linear model was carried out by adopting appropriate weights on the control inputs in the objective function. These weights were tuned to avoid actuator saturation via simulation. Experimental results showed that the ANFIS model was able to accurately replicate the response of the process to changes in temperature. Based on the ANFIS model, an MPC strategy was formulated for the process.

In this study, the throughput and kinetics of furfural production by the liquefaction of wet flax straw was conducted. The reaction was carried out in the temperature range of 200–325 °C, pressure of 0–60 bar, retention time in the range of 0–120 min, catalyst amount of 0.5–1.5 g, and a flax straw mass fraction of 10% using three types of solid acid catalysts: γ–alumina, H-ZSM-5, and silica-alumina. The results show that the highest yield of furfural was obtained using γ-alumina catalyst of weight of 1 g and the highest conversion of 66% at 325 °C. It was found that the acidity of the catalyst is key to enhance the production of furfural with a direct correlation with the number of the Lewis acid sites. The catalysts in order of the number of Lewis acid sites was found to be γ–alumina > H-ZSM-5 > silica-alumina. The kinetic data were also developed using an empirical rate model. The apparent activation energy was found to be 9.46 kJ/mol and the reaction order was 2.0. Also, the model-predicted rate showed a good agreement with the experimental rates with more than 91% accuracy.

Promoted ternary oxide based bimetallic catalysts with nominal composition of 3%Ni5%Cu/CeZrM (where M = La, Mg, Y, Gd or Ca) were prepared by surfactant-assisted route and tested for the high temperature water gas shift reaction. The catalysts were initially screened at 500 °C at atmospheric pressure in a packed bed tubular reactor using 30%CO/70%N 2 gas. The Ca promoted catalyst showed the best performance, and was subsequently tested using simulated reformate gas of composition: 46.2%CO, 8.5%CH 4 , 7.2%CO 2 and 38.1%H 2 (obtained from biogas dry reforming). Effects of catalyst preparation method: (i.e. impregnation method (atmospheric pressure or vacuum), surfactant/metal ratio (S/M = 0–1.25) and calcination temperature (425–650 °C) were tested. Operating conditions: (i.e. reaction temperature (450–550 °C), steam/CO molar ratio and reactor pressure (atmospheric–250 psi) were also studied. Structure-activity relationships developed to correlate catalyst characteristics to performance showed that catalyst activity was highly dependent on Cu reducibility, support basicity and metal dispersion.